U.S. patent application Ser. No. 08/808,511, filed Feb. 27, 1997, discloses a pneumatically controlled seating system in which an electronic control module selectively controls energization of a valve unit for controlling air flow from a pressure source to a plurality of pressurizable air cells.
The valve unit is a low energy consumption valve that is opened and closed by a valve actuator having a low consumption of power during operation of the system. One suitable valve for use in such systems is shown in U.S. Pat. No. 5,447,286 wherein a high flow valve is controlled by pilot air selectively delivered by a piezo vent valve. The piezo actuation is provided by a cantilevered member that has a layer of ceramic material bonded to a carrier plate. The ceramic material deforms when a voltage is imposed thereon by the control module. Deformation of the ceramic layer will deflect the carrier plate to open and close the vent valve that in turn controls the high flow valve.
While suitable for its intended purpose, the use of a cantilevered configured piezo actuator in the valve shown in U.S. Pat. No. 5,447,286 is not adaptable to ease of assembly in a valve module that controls air flow to a number of air cells. Furthermore, it is difficult to arrange such valves in a limited space within a valve module. Furthermore, in addition to the piezo vent valve, a high flow valve is required.